Displaying publications 21 - 40 of 42 in total

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  1. Zainalabidin S, Budin SB, Ramalingam A, Lim YC
    Korean J Physiol Pharmacol, 2014 Oct;18(5):411-8.
    PMID: 25352761 DOI: 10.4196/kjpp.2014.18.5.411
    Vascular remodelling is an adaptive mechanism, which counteracts pressure changes in blood circulation. Nicotine content in cigarette increases the risk of hypertension. The exact relationship between nicotine and vascular remodelling still remain unknown. Current study was aimed to determine the effect of clinically relevant dosage of nicotine (equivalent to light smoker) on aortic reactivity, oxidative stress markers and histomorphological changes. Twelve age-matched male Sprague-Dawley rats were randomly divided into two groups, i.e.: normal saline as control or 0.6 mg/kg nicotine for 28 days (i.p., n=6 per group). On day-29, the rats were sacrificed and the thoracic aorta was dissected immediately for further studies. Mean arterial pressure (MAP) and pulse pressure (PP) of nicotine-treated vs. control were significantly increased (p<0.05). Nicotine-treated group showed significant (p<0.05) increase tunica media thickness, and decrease in lumen diameter, suggesting vascular remodelling which lead to prior hypertension state. The phenylephrine (PE)-induced contractile response in nicotine group was significantly higher than control group (ED50=1.44×10(5) M vs. 4.9×10(6) M) (p<0.05~0.001). However, nicotine-treated rat showed significantly lower endothelium-dependent relaxation response to acetylcholine (ACh) than in control group (ED50=6.17×10(7) M vs. 2.82×10(7) M) (p<0.05), indicating loss of primary vascular function. Malondialdehyde (MDA), a lipid peroxidation marker was significantly higher in nicotine group. Superoxide dismutase (SOD) enzymatic activity and glutathione (GSH) were all reduced in nicotine group (p<0.05) vs. control, suggesting nicotine induces oxidative imbalance. In short, chronic nicotine administration impaired aortic reactivity, probably via redox imbalance and vascular remodelling mechanism.
  2. Yap WB, Ahmad FM, Lim YC, Zainalabidin S
    Korean J Physiol Pharmacol, 2016 Nov;20(6):621-628.
    PMID: 27847439
    Hypertension can be caused by various factors while the predominant causes include increase in body fluid volume and resistance in the circulatory system that elevate the blood pressure. Consumption of probiotics has been proven to attenuate hypertension; however, the effect is much strain-dependent. In this study, a newly isolated Lactobacillus casei (Lb. casei) strain C1 was investigated for its antihypertensive properties in spontaneously hypertensive rats (SHR). Lactic acid bacteria (LAB) suspension of 11 log colony-forming unit (CFU) was given to SHR (SHR+LAB, n=8), and phosphate buffer saline (PBS) was given as a control in SHR (SHR, n=8) and in Wistar rats as sham (WIS, n=8). The treatment was given via oral gavage for 8 weeks. The results showed that the weekly systolic blood pressure (SBP), mean arterial pressure (MAP), diastolic blood pressure (DBP) and aortic reactivity function were remarkably improved after 8 weeks of bacterial administration in SHR+LAB. These effects were mostly attributed by restoration of wall tension and tensile stress following the bacterial treatment. Although not statistically significant, the level of malondialdehye (MDA) in SHR+LAB serum was found declining. Increased levels of glutathione (GSH) and nitric oxide (NO) in SHR+LAB serum suggested that the bacterium exerted vascular protection through antioxidative functions and relatively high NO level that induced vasodilation. Collectively, Lb. casei strain C1 is a promising alternative for hypertension improvement.
  3. Samsudin MF, Lim YC, Rochmah TN, Dahlui M
    BMC Health Serv Res, 2024 Nov 16;24(1):1414.
    PMID: 39548435 DOI: 10.1186/s12913-024-11768-5
    BACKGROUND: The government has rapidly promoted the privatisation of healthcare to improve systemic performance, based on the theory that markets improve efficiency. This study aims to measure the efficiency of private hospitals following their expansion and venture into the medical tourism industry through extensive governmental support.

    METHODS: Inpatient utilisation of 101 private, non-specialised hospitals in Malaysia in 2014 and 2018 from the Health Informatics Centre, Ministry of Health Malaysia database was studied using paired samples t-test, analysis of variance (ANOVA), and the Pabón-Lasso model.

    RESULTS: Better quantitative performance was found among larger hospitals, those with hospital accreditation, and those participating in medical tourism activities. There is a scale effect of efficiency between smaller and larger hospitals. However, when compared within respective size categories, Category 1 (small hospitals with less than 100 beds) has the highest percentage of efficient hospitals (39.3 per cent in 2014 and 35.7 per cent in 2018 in Sector 3 of the Pabón Lasso graphs).

    CONCLUSION: This study has found that a higher bed occupancy rate (BOR) and longer average length of stay (ALoS) are associated with larger private hospitals, hospital accreditation, and participation in medical tourism activities in Malaysia. There is a need to expedite strategic hospitals partnership for resource optimisation and capacity pooling towards producing better performance.

  4. Yap JF, Wan Ahmad WA, Lim YC, Moy FM
    Ind Health, 2024 Aug 29.
    PMID: 39198183 DOI: 10.2486/indhealth.2024-0077
    Cardiovascular disease (CVD) caused substantial morbidity among occupationally active populations. However, data regarding the longitudinal burden of CVD were limited, particularly among school teachers. The objectives of our study were to estimate the incidence rate of CVD and determine its predictors among school teachers in Peninsular Malaysia through a prospective cohort study. We followed 14,046 eligible school teachers recruited between 2013 and 2014 until 31st December 2021. We accessed three computerised, country-level registries to determine incident CVD cases during the study period from 2013 to 2021. Baseline sociodemographic, lifestyle, work-related and clinical characteristics were recorded. Cox proportional hazard regression models with adjusted hazard ratio and 95% confidence interval were reported. With a median follow-up of 7.71 yr, we observed 209 incident CVD cases (or 195.7 CVD cases per 100,000 person-years). Male gender, age ≥40 yr old, Indian or others ethnicity (as compared to Chinese), family history of CVD, laboratory-confirmed diabetes mellitus, self-reported hypertension, high low-density lipoprotein cholesterol and high triglyceride were predictors for incident CVD among school teachers. Neither work-related nor lifestyle factors were significantly associated with incident CVD. Screening at-risk teachers for diabetes mellitus, hypertension or dyslipidemia is recommended to delay the onset or progression of CVD.
  5. Chin SF, Cheong SK, Lim YC, Mok KL, Hamidah HN
    Malays J Pathol, 1993 Dec;15(2):125-30.
    PMID: 8065173
    The applications of antibodies, be it monoclonal or polyclonal, in the diagnostic and research fields are well established. The disadvantage is the high cost of commercially available antibodies. In a diagnostic establishment like ours which also functions as a training ground for laboratory related personnel, it is beneficial to be able to produce in-house reagents. Therefore, we have undertaken this project to produce a rabbit polyclonal antibody against B lymphocytes. We found that the rabbit was a good choice because the titre of antibody produced was high and positive reactions were still detected at a dilution of 1:38400. The antibody showed significant positive reaction only with the lymphocyte subpopulation. A positive reaction was observed between the immunized rabbit serum and B lymphocytes but not T lymphocytes. This shows that the antibody was B lymphocyte specific. There was a positive correlation between the percentage of B lymphocytes labelled using the commercial anti-CD19 monoclonal antibody and the in-house polyclonal antibody (n = 13, r = 0.7, p = 0.02). However, the percentage of cells labelled by the in-house polyclonal anti-B was lower than that by the commercial monoclonal anti-CD19. The fluorescence intensity of the polyclonal antibody was lower than that of the monoclonal. In general, the performance of the in-house polyclonal antibody can be considered as satisfactory. The rabbit serum was stored at -20 degrees C and no significant loss of activity was detected for over a period of 19 months.
  6. Muhammad Nur Amir AR, Binti Amer Nordin A, Lim YC, Binti Ahmad Shauki NI, Binti Ibrahim NH
    Front Public Health, 2021;9:574135.
    PMID: 33643985 DOI: 10.3389/fpubh.2021.574135
    The COVID-19 pandemic that emerged in 2019 has inflicted numerous clinical and public health challenges worldwide. It was declared a public health emergency by the World Health Organization and activated response teams at almost all Malaysian healthcare facilities. Upon activation of the National Crisis Preparedness and Response Center in January 2020, the National Institutes of Health Malaysia established a COVID-19 operation room at the facility level to address the rise in COVID-19 infection cases each day. The National Institutes of Health COVID-19 operation room committee formed a workforce mobilization team for an effective and efficient mobilization system to fulfill requests received for human resource aid within the Ministry of Health Malaysia facilities. Selected personnel would be screened for health and availability before mobilization letters and logistics arrangements if necessary. The workforce from the National Institutes of Health, consisting of various job positions, were mobilized every week, with each deployment cycle lasting 2 weeks. A total of 128 personnel from the six institutes under the National Institutes of Health were mobilized: tasks included fever screening, active case detection, health management at quarantine centers, and management of dead bodies. A well-organized data management system with a centralized online system integration could allow more rapid deployment and answer some of the key questions in managing a similar pandemic in the future. With improving infected COVID-19 cases throughout the country, the National Institutes of Health COVID-19 operation room was effectively closed on June 15, 2020, following approval from the Deputy Director-General of Health.
  7. Mahmood I, Azfaralariff A, Mohamad A, Airianah OB, Law D, Dyari HRE, et al.
    PMID: 33737223 DOI: 10.1016/j.cbpc.2021.109033
    The ability of natural extracts to inhibit melanocyte activity is of great interest to researchers. This study evaluates and explores the ability of mutated Shiitake (A37) and wildtype Shiitake (WE) extract to inhibit this activity. Several properties such as total phenolic (TPC) and total flavonoid content (TFC), antioxidant activity, effect on cell and component profiling were conducted. While having no significant differences in total phenolic content, mutation resulted in A37 having a TFC content (1.04 ± 0.7 mg/100 ml) compared to WE (0.86 ± 0.9 mg/100 ml). Despite that, A37 extract has lower antioxidant activity (EC50, A37 = 549.6 ± 2.70 μg/ml) than WE (EC50 = 52.8 ± 1.19 μg/ml). Toxicity tests on zebrafish embryos show that both extracts, stop the embryogenesis process when the concentration used exceeds 900 μg/ml. Although both extracts showed pigmentation reduction in zebrafish embryos, A37 extract showed no effect on embryo heartbeat. Cell cycle studies revealed that WE significantly affect the cell cycle while A37 not. Further tests found that these extracts inhibit the phosphorylation of Glycogen synthase kinase 3 β (pGSK3β) in HS27 cell line, which may explain the activation of apoptosis in melanin-producing cells. It was found that from 19 known compounds, 14 compounds were present in both WE and A37 extracts. Interestingly, the presence of decitabine in A37 extract makes it very potential for use in the medical application such as treatment of melanoma, skin therapy and even cancer.
  8. Si LY, Kamisah Y, Ramalingam A, Lim YC, Budin SB, Zainalabidin S
    Appl Physiol Nutr Metab, 2017 Jul;42(7):765-772.
    PMID: 28249121 DOI: 10.1139/apnm-2016-0506
    Vascular endothelial dysfunction (VED) plays an important role in the initiation of cardiovascular diseases. Roselle, enriched with antioxidants, demonstrates high potential in alleviating hypertension. This study was undertaken to investigate the effects of roselle supplementation of VED and remodelling in a rodent model with prolonged nicotine administration. Male Sprague-Dawley rats (n = 6 per group) were administered with 0.6 mg/kg nicotine for 28 days to induce VED. The rats were given either aqueous roselle (100 mg/kg) or normal saline orally 30 min prior to nicotine injection daily. One additional group of rats served as control. Thoracic aorta was isolated from rats to measure vascular reactivity, vascular remodelling and oxidative stress. Roselle significantly lowered aortic sensitivity to phenylephrine-induced vasoconstriction (Endo-(+) Cmax = 234.5 ± 3.9%, Endo-(-) Cmax = 247.6 ± 5.2%) compared with untreated nicotine group (Endo-(+) Cmax = 264.5 ± 6.9%, Endo-(-) Cmax = 276.5 ± 6.8%). Roselle also improved aortic response to endothelium-dependent vasodilator, acetylcholine (Endo-(+) Rmax = 73.2 ± 2.1%, Endo-(-) Rmax = 26.2 ± 0.8%) compared to nicotine group (Endo-(+) Rmax = 57.8 ± 1.7%, Endo-(-) Rmax = 20.9 ± 0.8%). In addition, roselle prevented an increase in intimal media thickness and elastic lamellae proliferation to preserve vascular architecture. Moreover, we also observed a significantly lowered degree of oxidative stress in parallel with increased antioxidant enzymes in aortic tissues of the roselle-treated group. This study demonstrated that roselle prevents VED and remodelling, and as such it has high nutraceutical value as supplement to prevent cardiovascular diseases.
  9. Lim YC, Quek H, Offenhäuser C, Fazry S, Boyd A, Lavin M, et al.
    J Neurooncol, 2018 Jul;138(3):509-518.
    PMID: 29564746 DOI: 10.1007/s11060-018-2838-0
    Glioblastoma (GBM) is a highly fatal disease with a 5 year survival rate of less than 22%. One of the most effective treatment regimens to date is the use of radiotherapy which induces lethal DNA double-strand breaks to prevent tumour growth. However, recurrence occurs in the majority of patients and is in-part a result of robust radioresistance mechanisms. In this study, we demonstrate that the multifunctional cytokine, interleukin-6 (IL-6), confers a growth advantage in GBM cells but does not have the same effect on normal neural progenitor cells. Further analysis showed IL-6 can promote radioresistance in GBM cells when exposed to ionising radiation. Ablation of the Ataxia-telangiectasia mutated serine/threonine kinase that is recruited and activated by DNA double-strand breaks reverses the effect of radioresistance and re-sensitised GBM to DNA damage thus leading to increase cell death. Our finding suggests targeting the signaling cascade of DNA damage response is a potential therapeutic approach to circumvent IL-6 from promoting radioresistance in GBM.
  10. Tsiamis A, Diaz Sanchez F, Hartikainen N, Chung M, Mitra S, Lim YC, et al.
    ACS Omega, 2021 Apr 27;6(16):10568-10577.
    PMID: 34056211 DOI: 10.1021/acsomega.0c05823
    This paper presents a scalable method of developing ultrasensitive electrochemical biosensors. This is achieved by maximizing sensor conductivity through graphene wrapping of carbonized electrospun nanofibers. The effectiveness of the graphene wrap was determined visually by scanning electron microscopy and chemically by Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The sensing performance of different electrode samples was electrochemically characterized using cyclic voltammetry and electrochemical impedance spectroscopy, with the graphene-wrapped carbonized nanofiber electrode showing significantly improved performance. The graphene-wrapped carbonized nanofibers exhibited a relative conductivity of ∼14 times and an electroactive surface area of ∼2 times greater compared to the bare screen-printed carbon electrode despite experiencing inhibitive effects from the carbon glue used to bind the samples to the electrode. The results indicate potential for a highly conductive, inert sensing platform.
  11. Chong ZL, Lodz NA, Mutalip MHA, Lim YC, Mahjom M, Ahmad NA
    Western Pac Surveill Response J, 2021 09 03;12(3):71-76.
    PMID: 34703638 DOI: 10.5365/wpsar.2021.12.3.842
    Problem: The novel coronavirus disease 2019 (COVID-19) pandemic adversely affected the preparation of Malaysia's National Health and Morbidity Survey for 2020 because conducting it would expose data collectors and participants to an increased risk of infection.

    Context: The survey is nationally representative and community based and is conducted by the Institute for Public Health, part of the National Institutes of Health, to generate health-related evidence and to support the Malaysian Ministry of Health in policy-making. Its planned scope for 2020 was the seroprevalence of communicable diseases such as hepatitis B and C.

    Action: Additional components were added to the survey to increase its usefulness, including COVID-19 seroprevalence and facial anthropometric studies to ensure respirator fit. The survey's scale was reduced, and data collection was changed from including only face-to-face interviews to mainly self-administered and telephone interviews. The transmission risk to participants was reduced by screening data collectors before the survey and fortnightly thereafter, using standard droplet and contact precautions, ensuring proper training and monitoring of data collectors, and implementing other administrative infection prevention measures.

    Outcome: Data were collected from 7 August to 11 October 2020, with 5957 participants recruited. Only 4 out of 12 components of the survey were conducted via face-to-face interview. No COVID-19 cases were reported among data collectors and participants. All participants were given their hepatitis and COVID-19 laboratory test results; 73 participants with hepatitis B and 14 with hepatitis C who had been previously undiagnosed were referred for further case management.

    Discussion: Preparing and conducting the National Health and Morbidity Survey during the COVID-19 pandemic required careful consideration of the risks and benefits, multiple infection prevention measures, strong leadership and strong stakeholder support to ensure there were no adverse events.

  12. Remali J, Aizat WM, Ng CL, Lim YC, Mohamed-Hussein ZA, Fazry S
    PeerJ, 2020;8:e9197.
    PMID: 32509463 DOI: 10.7717/peerj.9197
    BACKGROUND: DNA double strand break repair is important to preserve the fidelity of our genetic makeup after DNA damage. Rad50 is one of the components in MRN complex important for DNA repair mechanism. Rad50 mutations can lead to microcephaly, mental retardation and growth retardation in human. However, Rad50 mutations in human and other organisms have never been gathered and heuristically compared for their deleterious effects. It is important to assess the conserved region in Rad50 and its homolog to identify vital mutations that can affect functions of the protein.

    METHOD: In this study, Rad50 mutations were retrieved from SNPeffect 4.0 database and literature. Each of the mutations was analyzed using various bioinformatic analyses such as PredictSNP, MutPred, SNPeffect 4.0, I-Mutant and MuPro to identify its impact on molecular mechanism, biological function and protein stability, respectively.

    RESULTS: We identified 103 mostly occurred mutations in the Rad50 protein domains and motifs, which only 42 mutations were classified as most deleterious. These mutations are mainly situated at the specific motifs such as Walker A, Q-loop, Walker B, D-loop and signature motif of the Rad50 protein. Some of these mutations were predicted to negatively affect several important functional sites that play important roles in DNA repair mechanism and cell cycle signaling pathway, highlighting Rad50 crucial role in this process. Interestingly, mutations located at non-conserved regions were predicted to have neutral/non-damaging effects, in contrast with previous experimental studies that showed deleterious effects. This suggests that software used in this study may have limitations in predicting mutations in non-conserved regions, implying further improvement in their algorithm is needed. In conclusion, this study reveals the priority of acid substitution associated with the genetic disorders. This finding highlights the vital roles of certain residues such as K42E, C681A/S, CC684R/S, S1202R, E1232Q and D1238N/A located in Rad50 conserved regions, which can be considered for a more targeted future studies.

  13. Samsudin NA, Zainal Z, Lim HN, Sulaiman Y, Chang SK, Lim YC, et al.
    RSC Adv, 2018 Jun 21;8(41):23040-23047.
    PMID: 35540159 DOI: 10.1039/c8ra03513j
    In this study, a composite material, manganese oxide/reduced titania nanotubes (Mn2O3/R-TNTs), was synthesized through incorporation of Mn2O3 onto R-TNTs via the reverse pulse electrodeposition technique. The influence of pulse reverse duty cycles on the morphological, structural and electrochemical performance of the surface was studied by varying the applied duty cycle from 10% to 90% for 5 min total on-time at an alternate potential of -0.90 V (E on) and 0.00 V (E off). FESEM analysis revealed the uniform deposition of Mn2O3 on the circumference of the nanotubes. The amount of Mn2O3 loaded onto the R-TNTs increased as a higher duty cycle was applied. Cyclic voltammetry and galvanostatic charge-discharge tests were employed to elucidate the electrochemical properties of all the synthesized samples in 1 M KCl. The specific capacitance per unit area was greatly enhanced upon the incorporation of Mn2O3 onto R-TNTs, but showed a decrease as a high duty cycle was applied. This proved that low amounts of Mn2O3 loading enhanced the facilitation of the active ions for charge storage purposes. The optimized sample, Mn2O3/R-TNTs synthesized at 10% duty cycle, exhibited high specific capacitance of 18.32 mF cm-2 at a current density of 0.1 mA cm-2 obtained from constant current charge-discharge measurements. This revealed that the specific capacitance possessed by Mn2O3/R-TNTs synthesized at 10% duty cycle was 6 times higher than bare R-TNTs.
  14. Lim SH, Lim YC, Zaki RA, Johari BM, Chang CY, Omar SFS, et al.
    PLoS One, 2024;19(4):e0298376.
    PMID: 38626017 DOI: 10.1371/journal.pone.0298376
    BACKGROUND: Post Acute COVID Syndrome (PACS), a complex and poorly understood condition characterised by persistent symptoms following the acute phase of COVID-19 infection, has emerged as a significant global health concern. Healthcare workers who had been at the forefront of the pandemic response are at heightened risk of contracting the virus and subsequently developing PACS. Therefore, we aim to determine the prevalence and risk factors for PACS among healthcare workers infected with COVID-19.

    METHODS: A cross-sectional study was conducted between October 2022 and August 2023 using an online REDCap electronic data capture tool questionnaire. PACS was defined as new or persistent symptoms lasting more than 28 days after a positive SARS-CoV-2 polymerase chain reaction or rapid test kit antigen test. Multivariable logistic regression was performed to determine predictors associated with PACS.

    RESULTS: Among 609 infected healthcare workers, they were predominantly female (71.8%), Malays (84.6%), and aged 18-39 years (70.1%). 50.7% of infected healthcare workers experienced PACS. The most common PACS symptoms experienced were fatigue (27.9%), cough (25.1%), decreased physical strength (20.5%), and musculoskeletal pain (19.2%). Those who are more likely to develop PACS were females, underlying asthma, and COVID-19 severity category 3. On the other hand, those who received booster vaccinations were less likely to develop PACS.

    CONCLUSION: PACS is prevalent among healthcare workers with COVID-19 at the University Malaya Medical Centre. These findings emphasise the critical need for those with higher risk to receive regular health monitoring and checkups to detect any early signs of PACS. It underscores the need for continuous support and healthcare interventions to mitigate the impacts of PACS and ensure the physical and mental well-being of healthcare workers.

  15. Ravichandran J, Woon SY, Quek YS, Lim YC, Noor EM, Suresh K, et al.
    Am J Med, 2019 03;132(3):362-366.
    PMID: 30503877 DOI: 10.1016/j.amjmed.2018.11.017
    PURPOSE: The purpose of this study was to examine the association of circulating concentrations of high-sensitivity cardiac troponin I (hs-cTn) in the various trimesters of pregnancy in patients with and without hypertension.

    METHODS: This was a prospective cross-sectional study of pregnant and postnatal women aged between 18-35 years with no coexisting diseases. Serum samples were analysed for hs-TnI.

    RESULTS: A total of 880 women (mean age = 29.1 years [standard deviation = 5.1 years]) were recruited with 129 (14%), 207 (24%), and 416 (47%) patients in the first, second, and third trimesters, respectively. Ninety (10%) participants were recruited in the postnatal period. During pregnancy 28 (3%) patients were classified as having pregnancy-induced hypertension and 10 (1%) as preeclampsia. High-sensitivity cardiac troponin I was measurable in 546 (62%) participants with a median of 1 ng/L (range 0 to 783 ng/L). Troponin concentrations were above the 99th percentile in 19 (2%) individuals. Patients with pregnancy-induced hypertension and preeclampsia had higher concentrations of hs-TnI (median 11 ng/L [interquartile range (IQR) 6 to 22 ng/L] vs 12ng/L [IQR 3 to 98 ng/L] vs 1 ng/L [IQR 0 to 1 ng/L]). In logistic regression modeling hs-cTnI concentration remained an independent predictor of pregnancy-induced hypertension or preeclampsia in both unadjusted and adjusted models (odds ratio 9.3 [95% confidence interval 5.8 to 16.3] and 11.5 [95% confidence interval 6.3 to 24.1], respectively, per doubling of hs-TnI concentrations).

    CONCLUSIONS: Cardiac troponin measured using a high-sensitivity assay is quantifiable in the majority of young pregnant women with 2% of individuals having concentration above the 99th percentile sex-specific threshold. Patients with pregnancy-induced hypertension or preeclampsia had higher cardiac troponin concentrations. Cardiac troponin was a strong independent predictor of pregnancy-induced hypertension or preeclampsia in pregnant and postnatal women.

  16. Cullen JK, Abdul Murad N, Yeo A, McKenzie M, Ward M, Chong KL, et al.
    PLoS One, 2016;11(2):e0148213.
    PMID: 26866375 DOI: 10.1371/journal.pone.0148213
    Autosomal recessive ataxias are a clinically diverse group of syndromes that in some cases are caused by mutations in genes with roles in the DNA damage response, transcriptional regulation or mitochondrial function. One of these ataxias, known as Autosomal Recessive Cerebellar Ataxia Type-2 (ARCA-2, also known as SCAR9/COQ10D4; OMIM: #612016), arises due to mutations in the ADCK3 gene. The product of this gene (ADCK3) is an atypical kinase that is thought to play a regulatory role in coenzyme Q10 (CoQ10) biosynthesis. Although much work has been performed on the S. cerevisiae orthologue of ADCK3, the cellular and biochemical role of its mammalian counterpart, and why mutations in this gene lead to human disease is poorly understood. Here, we demonstrate that ADCK3 localises to mitochondrial cristae and is targeted to this organelle via the presence of an N-terminal localisation signal. Consistent with a role in CoQ10 biosynthesis, ADCK3 deficiency decreased cellular CoQ10 content. In addition, endogenous ADCK3 was found to associate in vitro with recombinant Coq3, Coq5, Coq7 and Coq9, components of the CoQ10 biosynthetic machinery. Furthermore, cell lines derived from ARCA-2 patients display signs of oxidative stress, defects in mitochondrial homeostasis and increases in lysosomal content. Together, these data shed light on the possible molecular role of ADCK3 and provide insight into the cellular pathways affected in ARCA-2 patients.
  17. Pahrol MA, Ismail R, Mohamad N, Lim YC, Muhamad Robat R, Rajendiran S, et al.
    Front Public Health, 2023;11:1028443.
    PMID: 36935685 DOI: 10.3389/fpubh.2023.1028443
    INTRODUCTION: Healthcare workers (HCWs) have been continually exposed to patients with COVID-19 and are at higher risk of contracting the disease. Their psychological health is important for overall wellbeing and productivity, which could lead to a reduction in human errors during the pandemic crisis. This study aimed to measure the level of concerns, work practices, adequacy of preventive measures among HCWs, and the impacts on their life and work, including mental health status during the second wave of the COVID-19 pandemic in Malaysia.

    METHODS: An online questionnaire was distributed randomly to 1,050 HCWs from the Ministry of Health facilities in the Klang Valley who were involved directly in managing or screening COVID-19 cases from May to August 2020. The questionnaire was divided into five domains, which were concerns, impact on life and work, practice, perceived adequacy of preventive measures, and Revised Impact of Event Scale (IES-R). Logistic regression was used to identify sociodemographic predictors of the five domains.

    RESULTS: A total of 907 respondents (86.4%) participated in this survey. Approximately half of the respondents had a low concern (50.5%), most of them had a good practice (85.1%), with 67.5% perceiving there were adequate preventive measures, and they perceived the outbreak had a low impact (92%) on their life and work. From the IES-R domain, 18.6% of respondents potentially suffered from post-traumatic stress disorder (PTSD).

    CONCLUSION: During the second wave of the COVID-19 outbreak in Malaysia, HCWs practiced high levels of precautions and preventive measures because they were aware of the risk of infection as an occupational hazard. With the adequate implementation of policy and control measures, the psychological wellbeing of the majority HCWs remained well and adequately supported.

  18. Khairul Hasni NA, Ismail R, Muhamad Robat R, Mohamad N, Suib FA, Pahrol MA, et al.
    PLoS One, 2023;18(11):e0288105.
    PMID: 38019763 DOI: 10.1371/journal.pone.0288105
    This study examined the association of various brands of NIOSH-certified N95 filtering face-piece respirators (FFR) fit with facial dimensions and gender. One hundred and thirty-five participants (77 females and 58 males) were recruited from the previous facial anthropometry study among Malaysians in 2020. Quantitative respirator fit testing of six FFR were performed using the TSI Portacount Pro+ 8038 which comprised of four exercises (bending over, talking, up-down head movement, and side to side head movement). An overall fit factor (FF) of ≥ 100 was considered a pass for each FFR. Analysis was done using T-test, Pearson's correlations, and generalised linear regression. The passing rates for the six FFR were 36.3% (Cup B), 50.4% (Trifold A), 54.1% (Duckbill A), 57.0% (Cup A), 74.1% (Trifold B), and 83.7% (Duckbill B). Both Duckbill B and Trifold B had the highest passing rates for both genders. However, certain FFR models (Cup B, Trifold A, Trifold B, and Duckbill A) fit better for participants with large facial size who were mostly males, while others (Cup A and Duckbill B) specifically fit better for those with small facial size, who were mostly females. This study showed significant positive effect of nose protrusion, nasal root and subnasale-sellion and the negative effect of menton-sellion, bigonial breadth and nose breadth on fit factors of various FFR. The results of this study emphasized the importance of choosing and designing FFR based on local anthropometry data, with careful consideration on the dimensions that affect the respirator fit. Since N95 are commonly used in the healthcare settings to prevent airborne transmission, the practice of respirator fit testing and selecting N95 with high passing rates for healthcare workers need to be emphasized.
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